1. Field of the Invention
The invention relates generally to a networked system of controlled machines, such as document processors, sharing a single control processing unit containing a host application for controlling the machines. More particularly, the invention concerns a mechanism for enabling relatively simple communication among a single application program and a plurality of controlled machines, such as document processors.
2. The Prior Art
With reference to FIG. 1, larger, more expensive document processors such as check processor 100 have conventionally been controlled by a dedicated central processing unit 102. This is true regardless of the speed of the check processing machine. Central processor 102 hosts the customer's application software and provides some (or all) of the data manipulation services for check processing machine 100. However, central processor 102 typically has excess processing power when used to control relatively low speed check processing machines 100. This means that a low speed check-processing machine 100 generally makes a very uneconomical use of a central processor 102 and its resident host application. Additionally, multiple host applications are burdened with the added complexity of coordinating data from each of their respective check-processing machines with each other.
An example of a “host application” is a program to control a check-processing machine in capturing preselected image types, deciding what type of endorsement to print on the check, and which sorting pocket should receive the processed document. Such a host application could additionally communicate with a remote site for transfer of captured images for purposes such as archiving, amount entry or remittance.
With reference to FIG. 2, traditional systems comprising a plurality of document processing machines 200a, 200b, and 200c require dedicated central processors 202a, 202b and 202c for each document processing machine 200a,b,c. 
Recently, the concept of a check reading/processing machine that is relatively small and economical enough to enable a bank to have several distributed such machines at each of its branches has been developed. This device, often referred to as a “teller/scanner” machine, is designed to quickly preprocess checks at the intake point of the branch office and to send data to a host computer at the financial institution's central processing center. This results in faster and more economical processing of the banking documents. This new teller/scanner device has been found best utilized in a network of a plurality of such teller/scanners. However, to avoid wasting excess capacity of associating a controlling processor unit with each of the multiple teller/scanner units, there is seen to be a need in the field of document processor systems for simplifying application host programs used by a plurality of machines while eliminating wasted processing capacity of multiple central processors.